Method of forming composite ignitions or induction coils



Oct. 26, 1954 ELUOTT 2,692,423

METHOD OF FORMING COMPOSITE IGNITIONS OR INDUCTION COILS Filed June 4,1952 INVENTOR.

744% a gz/zoz'z.

Patented Oct. 26, 1954 METHOD OF FORMING COMPOSITE IGNITIONS ORINDUCTION COILS Ralph J. Elliott, Royal Oak, Mich. Application June 4,1952, Serial No. 291,715 2 Claims. (01. 29-155.58)

This invention relates to an improved method of assembling theindividual members or elements of composite ignition or induction coilsof the type used for ignition apparatus of internal combustion engines.

In the past, in the assembling of many types of such coils, the methodused was cumbersome and costly to the manufacturer, the assembling ofthe device taking many steps and cousuming a great deal of valuabletime. In the instant disclosure there is set forth a new and improvedmethod of assembling such coils which is not only more eiiicient thanthe method formerly used, but the end result is a better performingcoil.

The above and other objects will appear more fully from the followingmore detailed description of the invention, and from the drawing,wherein:

Fig. 1 is a view of the parts or members of the assembly as they areabout to be inserted within the can portion of the assembly.

Fig. 2 is a vertical section of the device.

Fig. 3 is a horizontal section taken substantially on line 33 of Fig. 2;and

Fig. 4. is a perspective view of the insulating tube member.

Referring now to the drawing, the numeral 10 designates an outer can orsheath member made of metal and open at one end thereof, the same beingadapted to receive plate members ll, said plate members being of metal,approximately the same height as the can member l and bent to form anare so that they will conveniently nest within each other, as shown bestin Fig. 3. An

insulating tube member [2 is provided, Fig. 4, the

same being constructed of non-electric conducting paperboard materialhaving sufiicient rigidity to maintain its shape and constructed, forexample, of a kraft and chipboard material saturated with a high meltingpoint asphaltic material, or other suitable thermoplastic insulatingbinder. These tubes may be manufactured in extra long lengths and cut tosize as desired. If desired a plurality of notches [3 may be provided inone end of the tube to allow freedom or, even flow and distribution of ahot binder, such as a pitch or asphaltic substance in the final assemblyof the coil, later to be described. Although notches are shown herein,these apertures may be of any design or construction, just so long asthey allow freedom of flow of the binding substance which serves thefunction of rigidly securing the tube 12, plates I I and the can memberl0 into an integral unitary relationship. The numeral I4 designates awell-known ignition or induction coil member per se, of conventionaldesign, adapted to fit snugly within insulating tube [2.

In the past it has been the practice in assembling coils as aboveoutlined, to first insert plates H within can member 10 in opposedpairs, each pair being comprised of two plates in abutting nestedrelationship, and spaced apart, as shown best in Fig. 1. The hot asphaltor other thermoplastic binding material is then poured into can member16 to substantially cover the bottom of the can member. Coil I4 is thenwrapped in a piece of treated tar paper which forms a separator betweenthe coil l4 and the metal plates II, and then, while holding the platesin separated positions within the can 10, the coil member 14 with thetar paper wrapping thereon, is slid into position down into the can. Theabove outlined steps take considerable time and are very cumbersome, theassembler having to keep in mind at all times that the plates ll must beproperly spaced apart within the inner periphery of the can [0. Whileholding the plates in position with the fingers of one hand it isnecessary to thread the coil member 14 with its tar paper wrappingbetween the plates II and down into the hot asphaltic substance in thebottom of can It). The primary difficulty in the hand assembling methodabove outlined lies in the close fit between the coil member I 4surrounded by the tar paper wrapping thereon and the inner surfaces ofplates II.

In carrying out my new method of assembling induction coils I provide anew open ended insulating tube member which is prefabricated in longlengths and cut to size, the same comprising a chipboard and/or kraftmaterial saturated with a high melting point asphalt, or the like, inbutted and overlapping plies, the finished product providing anefficient insulating material. In the periphery of one end of the tubethere may be cut a plurality of notches or openings of other shapes, ifdeemed essential, to allow the hot asphalt or other thermoplasticbinding material, which is placed in the bottom of the can member 10, toflow freely therethrough so that the same will contact the coil memberM. In my new method of assembling the induction coil, the assemblertakes insulating tube l2 and places the plates I l against the outerperiphery thereof, said plates being arc-shaped they nest in pairs oftwo and are placed against said tube so that there are opposed gaps,Fig. 1. The plates, held against the tube, are then inserted into canmember Ill, said tube holding the plates firmly against the innerperiphery of said can member. Hot asphaltic material is then poured intothe can member, suflicient to cover the bottom of the can. The coilmember [4 is then inserted into tube 12 and the assembly allowed to coolwith hardening of the asphaltic binder thereby forming a unitaryinduction coil assembly.

There has been disclosed herein a new openended insulating tube andmethod of assembling ignition or induction coils, which, in actualpractice, has proven a great time and money saver to I the manufacturersof such coils. Instead of the old type tar-paper, which has to be cut tosize each time it is used and wrapped about the coil member of thedevice, I provide a prefabricated insulating tube which is adapted toreceive opposed plates which can be held against the outside of the tubewhile the tube and plates are inserted within the outer can member ofthe device. A hot asphaltic material is then poured into the can memberand the coil member quickly inserted into the insulating tube within thecan, the entire operation taking seconds instead of minutes as with theold method of assembly.

While certain ways of carrying out the invention have been quitespecifically disclosed and certain variations have been described, otherchanges may be made within the scope of the invention as defined in theappended claims.

I claim:

1. In the assembling of induction coils and the like wherein acylindrical induction coil member and spaced arcuate metal plate membersare to be assembled within an outer cup-like sheath member in insulatedrelation to each other, the

steps which comprise positioning the plate members in spaced relation onthe periphery of a preformed cylindrical insulating tube member havingsubstantial rigidity to retain its shape the insulating tube memberbeing provided with a plurality of openings around the outer peripheryto allow free flow of molten binding material thereto, inserting theassembled arcuate plate members and insulating tube member within thesheath member, pouring molten binding material into the sheath memberafter the insertion of the insulating tube member and arcuate platemembers to bind the insulating tube member and plate members to theinterior of the sheath member, and thereafter inserting an inductioncoil member or the like within the cylindrical insulating tube memberand then allowing the assembly to 0001, thereby forming a unitarydevice, the sheath, arcuate plate, insulating tube and induction coilmembers of the assembly being of such relative sizes that the membersare snugly nested when assembled in the order stated above.

2. A method as set forth in claim 1, wherein the insulating tube memberis formed of paperboard material saturated with a high melting pointthermoplastic insulating binder.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 981,129 Seigle Jan. 10, 1911 1,640,543 Gudge Aug. 30, 19271,878,606 Schneider et a1. Sept. 20, 1932 35 1,977,122 Ehrlich et a1Oct. 16, 1934

